Monthly Archives: August 2019

QR code decoding by zxing

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package com.ns.utils;

import java.awt.image.BufferedImage;
import java.io.IOException;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.HashMap;
import java.util.Hashtable;
import java.util.Map;
import java.util.Vector;

import org.apache.pdfbox.pdmodel.PDDocument;
import org.apache.pdfbox.rendering.ImageType;
import org.apache.pdfbox.rendering.PDFRenderer;

import com.google.zxing.BarcodeFormat;
import com.google.zxing.BinaryBitmap;
import com.google.zxing.DecodeHintType;
import com.google.zxing.LuminanceSource;
import com.google.zxing.MultiFormatReader;
import com.google.zxing.NotFoundException;
import com.google.zxing.Result;
import com.google.zxing.client.j2se.BufferedImageLuminanceSource;
import com.google.zxing.common.HybridBinarizer;

public class QRCodeZxingUtil {

	public static Map<String, String> scanQRCode(String dir, String fileName, String textKey) {
		Map<String, String> mp = new HashMap<String, String>();
		// Hints for scanning
		Vector<BarcodeFormat> decodeFormat = new Vector<BarcodeFormat>();
		decodeFormat.add(BarcodeFormat.QR_CODE);

		Hashtable<DecodeHintType, Object> hintMap = new Hashtable<DecodeHintType, Object>();
		hintMap.put(DecodeHintType.TRY_HARDER, true);
		hintMap.put(DecodeHintType.POSSIBLE_FORMATS, decodeFormat);

		MultiFormatReader qrcodeReader = new MultiFormatReader();
		qrcodeReader.setHints(hintMap);
		// We try for several images of the PDF page at several DPI settings,
		// starting at the lowest setting, this might help for speed...
		int[] dpiSettings = { 96, 150, 200, 250, 300, 350 };
		for (int i = 0; i < dpiSettings.length; i++) {
			try {
				// Try lowest DPI first.
				BufferedImage pageImage = getPageImage(dir, fileName, dpiSettings[i]);
				if (pageImage != null) {
					LuminanceSource source = new BufferedImageLuminanceSource(pageImage);
					BinaryBitmap bitmap = new BinaryBitmap(new HybridBinarizer(source));
					// By using decodeWithState, we keep the Hints that we set earlier.
					Result result = qrcodeReader.decodeWithState(bitmap);
					String text = result.getText();
					// System.out.println(" Sucess at DPI -> " + dpiSettings[i]);
					pageImage.flush();

					if (text != null && text.length() > 0) {
						mp.put(textKey, text);
						mp.put("DPI", Integer.toString(dpiSettings[i]));
					}
				}
				if (mp.containsKey(textKey)) {
					return mp;
				}
			} catch (IOException e) {
				System.out.print(" IOException at DPI -> " + dpiSettings[i]);
			} catch (NotFoundException e) {
				System.out.print(" NotFoundException at DPI -> " + dpiSettings[i]);
			}
		}
		return null;
	}

	private static BufferedImage getPageImage(String dir, String fileName, int dpi) throws IOException {
		BufferedImage image = null;
		Path docPath = Paths.get(dir.concat(fileName));
		PDDocument pdfDoc = PDDocument.load(docPath.toFile());
		try {
			PDFRenderer renderer = new PDFRenderer(pdfDoc);
			image = renderer.renderImageWithDPI(0, dpi, ImageType.BINARY); // entire page info
		} finally {
			pdfDoc.close();
		}		
		return image;
	}
}

QR code decoding by pdmodel

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package com.ns.utils;

import java.awt.image.BufferedImage;
import java.io.IOException;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.Collection;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import org.apache.pdfbox.pdmodel.PDDocument;
import org.apache.pdfbox.pdmodel.PDPage;
import org.apache.pdfbox.pdmodel.PDResources;
import org.apache.pdfbox.pdmodel.graphics.xobject.PDXObject;
import org.apache.pdfbox.pdmodel.graphics.xobject.PDXObjectImage;

import com.ns.service.QRCodeDecoder;

public class QRCodePdModelUtil {

	@SuppressWarnings("unchecked")
	public static Map<String, String> scanQRCode(String dir, String fileName, String textKey) {

		Map<String, String> map = new HashMap<String, String>();

		List<PDPage> pages = null;
		BufferedImage qrCodeImg = null;
		String qrCode = null;
		PDDocument pdfDoc = null;

		try {
			Path docPath = Paths.get(dir.concat(fileName));
			pdfDoc = PDDocument.load(docPath.toFile());
			QRCodeDecoder decoder = new QRCodeDecoder();

			pages = pdfDoc.getDocumentCatalog().getAllPages();
			int dpi = 0;
			int dpiEffective = 0;
			int dpiLow = 0;

			for (PDPage page : pages) {
				try {
					if (null == qrCode) {
						qrCodeImg = page.convertToImage(BufferedImage.TYPE_BYTE_GRAY, 100);
						qrCode = decoder.getCompressedQRCode(qrCodeImg);
					}
					if (null == qrCode) {
						dpi = detectPageDPI(page);
						dpiEffective = dpi;
						dpiLow = dpi - 5;
						for (; dpiLow < dpiEffective; dpiEffective--) {
							qrCodeImg = page.convertToImage(BufferedImage.TYPE_BYTE_GRAY, dpiEffective);
							qrCode = decoder.getCode(qrCodeImg);
							if (null != qrCode) {
								break;
							}
						}
					}
					if (null == qrCode) {
						qrCodeImg = page.convertToImage(BufferedImage.TYPE_BYTE_GRAY, 400);
						qrCode = decoder.getCompressedQRCode(qrCodeImg);
					}
					System.out.println("Code:::" + qrCode);
					if (null != qrCode) {
						map.put("DPI", Integer.toString(dpi));
						map.put(textKey, qrCode);
						return map;
					}
				} catch (Exception e) {
					System.out.println(e.getMessage());

				} finally {
					qrCodeImg = null;
					qrCode = null;
				}
			}
		} catch (IOException e) {
			e.printStackTrace();
		} catch (Exception e) {
			e.printStackTrace();
		} finally {
			if (null != pdfDoc) {
				try {
					pdfDoc.close();
				} catch (IOException e) {
					e.printStackTrace();
				}
			}
			pages = null;
		}
		return null;
	}

	private static int detectPageDPI(PDPage page) {
		PDResources res = page.getResources();
		Collection<PDXObject> xObjects = res.getXObjects().values();
		int imgHeight = 0;
		for (PDXObject xObject : xObjects) {
			if (xObject instanceof PDXObjectImage) {
				imgHeight = ((PDXObjectImage) xObject).getHeight();
			}
		}

		float pageHeight = page.getMediaBox().getHeight() / 72;
		int dpi = (int) (imgHeight / pageHeight);
		if (200 > dpi) {
			dpi = 200;
		}
		if (300 < dpi) {
			dpi = 300;
		}
		return dpi;
	}

}


package com.ns.service;

import java.awt.RenderingHints;
import java.awt.RenderingHints.Key;
import java.awt.image.BufferedImage;
import java.awt.image.BufferedImageOp;
import java.awt.image.ConvolveOp;
import java.awt.image.Kernel;
import java.awt.image.RasterFormatException;
import java.util.HashMap;
import java.util.Map;

import org.springframework.stereotype.Service;

import com.google.zxing.BinaryBitmap;
import com.google.zxing.ChecksumException;
import com.google.zxing.FormatException;
import com.google.zxing.LuminanceSource;
import com.google.zxing.NotFoundException;
import com.google.zxing.Result;
import com.google.zxing.client.j2se.BufferedImageLuminanceSource;
import com.google.zxing.common.HybridBinarizer;
import com.google.zxing.qrcode.QRCodeReader;

@Service
public class QRCodeDecoder {

	public String getCode(BufferedImage image) {
		String code = null;
		try {
			// vertical bottom scan
			BufferedImage procImage = image.getSubimage(0, image.getHeight() / 2, image.getWidth(), image.getHeight() / 2 - 20);
			code = decode(procImage);

		} catch (RasterFormatException e) {
			// continue
		}
		return code;
	}

	public String getCompressedQRCode(BufferedImage image) {
		String code = null;
		try {
			// vertical bottom scan
			BufferedImage procImage = image.getSubimage(150, image.getHeight() / 2, image.getWidth() - 150, image.getHeight() / 2 - 200);
			code = decode(procImage);
		} catch (RasterFormatException e) {
			// continue
		}
		return code;
	}

	public String decode(BufferedImage image) {
		RenderingHints hints = getRenderingHints();
		float[] kernelData = null;
		BufferedImageOp op = null;
		BufferedImage procImage = null;
		LuminanceSource source = null;
		BinaryBitmap bitmap = null;
		QRCodeReader reader = new QRCodeReader();
		Result result = null;
		String code = null;

		for (int denom = 10; denom <= 50; denom += 10) {
			try {
				procImage = image;
				float factor = (1.0f / ((float) denom));
				kernelData = getKernelData(factor);
				op = new ConvolveOp(new Kernel(4, 4, kernelData), ConvolveOp.EDGE_NO_OP, hints);
				source = new BufferedImageLuminanceSource(op.filter(procImage, null));
				bitmap = new BinaryBitmap(new HybridBinarizer(source));
				result = reader.decode(bitmap);
				code = result.getText();
				break;
			} catch (NotFoundException e) {
				// continue
			} catch (ChecksumException e) {
				// continue
			} catch (FormatException e) {
				// continue
			} finally {
				hints = null;
				kernelData = null;
				op = null;
				source = null;
				bitmap = null;
				procImage = null;
				result = null;
			}
		}
		return code;
	}

	protected RenderingHints getRenderingHints() {
		Map<Key, Object> map = new HashMap<Key, Object>();
		map.put(RenderingHints.KEY_INTERPOLATION, RenderingHints.VALUE_INTERPOLATION_BILINEAR);
		map.put(RenderingHints.KEY_RENDERING, RenderingHints.VALUE_RENDER_QUALITY);
		map.put(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
		RenderingHints hints = new RenderingHints(map);
		return hints;
	}

	protected float[] getKernelData(float data) {
		return new float[] { data, data, data, data, data, data, data, data, data, data, data, data, data, data, data, data };
	}
}